Massive stars vs Medium size stars

[Spacecake2]

My question is why can massive stars fuse heavier elements than helium contrary to medium sized stars like our sun. 

[Ags]

The bigger the star, the higher the pressure in the core.

[Spacecake2]

Oh. Stupid me

[900SL]

The sun can create around 80 elements during its life. Fusion continues above helium up to a point, and there are other nuclear synthesis processes at work

Edited April 17 by 900SL

[iantaylor2uk]

That may be true, but anything other than hydrogen and helium is present in extremely small amounts as the composition of our sun (by mass) is estimated at 92.1% hydrogen and 7.9% helium.

[900SL]

9 hours ago, iantaylor2uk said:

That may be true, but anything other than hydrogen and helium is present in extremely small amounts as the composition of our sun (by mass) is estimated at 92.1% hydrogen and 7.9% helium.

Currently.. it will change later though, as helium fuses upwards in the red giant phases? Which was how I understood the OPs question

[Gfamily]

A good article here, that summarises the routes by which elements are synthesized.

https://www.forbes.com/sites/startswithabang/2016/05/11/which-elements-will-never-be-made-by-our-sun/

Direct fusion in the sun works for a small number of lighter elements

Then there is the s-process, by which free neutrons released by some He fusion reactions can be captured piecemeal to synthesise some heavier elements. This will occur at the end of the sun's life when it goes into the red giant phase.

The process that the sun won't use to generate elements is the r-process, which occurs in supernovae, when the huge number of free neutrons can be rapidly absorbed to make a greater range of heavier elements. 

One thing I'm not sure about is whether there would be any significant recycling of s-process elements (generated in the core during the red giant phase) back into to the interstellar medium, or whether the elements will remain locked up in the white dwarf formed by the core of the sun where the elements were generated.

[Owmuchonomy]

It is all beautifully encompassed in the book 'Magic Furnace' by Marcus Chown.

[900SL]

9 hours ago, Owmuchonomy said:

It is all beautifully encompassed in the book 'Magic Furnace' by Marcus Chown.

It's Alchemy, I tell ya!

[TiffsAndAstro]

On 18/04/2024 at 20:08, 900SL said:

It's Alchemy, I tell ya!

Your knowledge of this subject seems in Dire Straits.

Edited Friday at 13:56 by TiffsAndAstro